1. Technical Field of the Invention
This invention relates to a rear seat lock for vehicles, with an anti-unlocking system incorporated, applicable to fold-down rear seats, of the type that have a set of locks with a latch or pawl and a trigger that turn, connected to a common spring and a bolt that is taken in by a recess in the trigger.
2. Prior Art
The lock is mounted on a base body and is situated either or on the bodywork of the vehicle, in combination with the corresponding bolt, which, in turn, is secured in reciprocation, either on the bodywork of the vehicle or on the fold-down seat.
The fundamental purpose of this type of lock is to enable to use of the seat by passengers, with the lock fastened, or fold down the seat to increase the boot space or carrying capacity, with the lock disengaged.
In the fastened or closed position, the lock must withstand the legal requirements and the manufacturers"" own specifications concerning safety in case of an accident.
One of the dynamic tests that the lock must withstand is a front impact test, in which it must support loads moving towards the forward part of the vehicle caused by the inertia of the masses of the seats themselves, passengers and luggage in the boot.
The important loads or weights are normally in the direction explained and all the locks on the market are designed in order to withstand them.
However, it so happens that in certain vehicle bodywork structures, loads appear in the opposite direction during a collision, moving towards the rear of the vehicle, which causes a reaction against the lock-bolt system, resulting in the involuntary opening of the system and therefore not fulfilling the safety requirements.
As shall be seen later in relation with FIG. 1 of the drawings, the trigger and the latch of the lock are normally in frontal surface contact in assemblies of this type, in which the said contact surface acts as a support and stop of the movement of the latch. Due to the reaction against the resulting loads moving backwards, the trigger immediately forces or pushes the bolt, and as they are in surface contact, turning or pivoting of the trigger takes place at very high speed or acceleration, so that once it makes contact with the latch, it causes it to move in the opening direction, while the latch in turn allows free turning of the trigger and the consequent unlocking of the bolt, which initially had been kept under control.
One object of the invention therefore is to provide a solution to the performance or behaviour of involuntary opening of the system in case of loads in a longitudinal direction and moving towards the rear part of the vehicle, while complying fully and absolutely with all the safety requirements.
For the putting into practice of this basic objective, the invention claims, in a lock of this type, provided with a latch and a trigger, with both being connected by a spring that tends to secure the closing position of the unit, the fact that both, latch and trigger, are offset in their frontal surface contact, with a security distance; the maintaining of an auxiliary surface contact between the two, in which the two surfaces in contact are arranged in such a way that the contact pressure passes through the turning or pivoting center of the latch in order to prevent accidental opening; the fact that the turning or pivoting of the latch is controlled in order to prevent transmission of movement from the trigger to the latch.
Alternatively, this last point claimed can be carried out by means of different practical solutions.